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164
METALLURGY OP IRON AND STEEL.
contains 13 per cent, of ash, and if the waste from the producer contains 87 per cent, of carbon, it would show that no work had been done in the producer and that there was 100 per cent, waste,
TABLE IX-C. Value Represented by Carbon in the Ash.
					Per Cent, of Total Heat Value Lost.			
Per Cent. Ash. in Coal.					4	7	10	13
20 per 40 50 60 70 80 85	cent. C	in as	hes		1.5 3.0 4.0 5.5 8.0 15.0 20.0	2.5 6.5 7.0 10.0 15.0 25.0	3.2 7.0 10.0 14.5 21.0	4.0 8.5 18.0 20.0
								
								
								
but if the coal contained only 4 per cent, ash and the ashes contained 87 per cent, carbon, it would show that only 30 per cent, of the coal had been wasted. The heat value represented by certain percentages of carbon in the ashes are given in Table IX-C. With a coal of 7 per cent, ash and with producer ash containing less than 0 per cent, of carbon, the loss of heat value is less than 2$ per cent, of the value of the coal, which is a radical difference from the' loss mentioned by von Jiiptner, wherein 20 per cent, of the total was thrown away.
(3)  Sensible heat in gas and steam.
The sensible heat of producer gas is wholly wasted, for in a regenerative furnace the gain in heat on the incoming end is balanced by the loss in hotter outgoing gases. In the experiment by von Jiiptner, the average temperature of the producer gas in four experiments is 267 C. I am inclined to doubt these temperatures, for von Jiiptner's loss from radiation and conduction alone was as much as all the factors in the Steelton practice combined, while the loss from sensible heat was low, on account of the low temperature of the escaping gases. The loss by radiation was determined by difference, and a cold fire should not give as much loss by radiation as a hot one, so that possibly von Jiiptner took the temperature of the gases at some distance from the producer and the item of radiation included part of the sensible heat of the gas. Under this